The present invention generally relates to microelectronic power regulation systems and components. More particularly, the invention relates to devices and systems for sensing power changes during operation of a microelectronic device.
Microelectronic power regulation systems generally include a power regulator configured to supply a desired, regulated power to a microelectronic device such as microprocessors, microcontrollers, memory devices, and the like. The system may also include capacitors located near and/or packaged with the microprocessor to supply additional charge during the operation of the microprocessor. Such power regulation systems are configured so that the power regulator (e.g., a switching regulator such as a Buck regulator) provides nominal operating power to the microprocessor and the capacitors supply charge to compensate for transient power demands that result from operation of the microelectronic device. Such transient power demands may occur, for example, when several transistors of the microprocessor switch in the same direction at approximately the same timexe2x80x94e.g., when a portion of the device is powered off to conserve power or a portion of the device is activated.
As the speed and integration of microprocessors increase, the use of power regulation systems that only employ decoupling capacitors to compensate for or regulate transient power demands becomes increasingly problematic. For example, the number and/or size of the capacitors required to account for transient events generally increases as the integration of the microprocessor increases. The capacitors take up a relatively large amount of space on the package and can be relatively expensive. In addition, as the speed and the performance of the microprocessor increases, the severity (e.g., the amplitude) of the transient power demands and the frequency of the events tend to increase. Further, the microelectronic devices often become more sensitive to degraded power waveforms, which result from transient events, as the integration and speed of the devices increase. Capacitors within typical power regulation systems may be unable to adequately regulate such severe transient power demands. If not regulated or filtered, transient power events may result in a power or ground xe2x80x9cspikexe2x80x9d or xe2x80x9cbouncexe2x80x9dxe2x80x94i.e., momentary voltage levels below or above the nominal operating voltage of the microelectronic device, which in turn induces bit errors in digital logic of the microelectronic device through degraded noise margin and supply-induced timing violations. Accordingly, improved apparatus for responding to transient events that result during operation of a microelectronic device are desired.
The present invention provides improved apparatus and techniques for sensing transient power demands during operation of a microelectronic device. When used in conjunction with power regulators, the sensing devices and techniques of the present invention allow for fast power regulation in response to sensed changes in power demand.
While the way in which the present invention addresses the disadvantages of the prior art will be discussed in greater detail below, in general, the present invention provides devices to measure change in current with respect to time (di/dt) and/or changes in voltage that occur during operation of a microelectronic device.
In accordance with one embodiment of the invention, the sense circuit is configured to reject or discount noise that is present on both a voltage supply line and a ground line. In accordance with one aspect of this embodiment, the circuit is configured to be substantially symmetrical, such that the inductance and resistance of the sense circuit portion on the voltage supply line or plane is substantially identical to the inductance and resistance on the ground sense circuit portion on the ground line or plane.
In accordance with another embodiment of the invention, the sense circuit is configured to minimize or reduce single-ended noise injection from either the supply voltage or the ground line. In accordance with one aspect of this embodiment of the invention, the sense circuit portion on the power supply line and portion on the ground line are substantially symmetric and spaced close to each other.
In accordance with yet another embodiment of the invention, a signal representative of a sensed power deviation is amplified. In accordance with one aspect of this embodiment of the invention, the sense signal is amplified by measuring di/dt across a relatively large inductorxe2x80x94such as parasitic inductance on a printed circuit board. In accordance with another aspect of this embodiment, di/dt signals from multiple lines are added together to amplify the signal associated with the rate of change of current.
In accordance with a further embodiment of the invention, the change in voltage is measured proximate the load, such that the measured change in voltage is indicative of the change in voltage at the load.